One Reddit user started a blog to discuss audio equipment repair projects to guide other aspiring hobbyists. The hope was that advertising revenue would materialize. Instead, repair jobs came to the surface, says the commenter who launched the side gig a few years ago. It was only a matter of time before a stranger reached out and said, "Hey, I saw you fixed a radio. I have that same radio, and money. Can we work something out?" Today, the commenter owns a stereo repair shop and regularly shares free equipment repair tips with fellow Redditors.

Another Reddit commenter, who goes by the handle Manthamon, described launching a company after years of undergoing professional airbrush tans for $50 a pop. By purchasing a mobile spray tan unit and mixing custom solutions, Manthamon built a business from the ground up--eventually opening a salon adjacent to a hairdresser who shares client referrals.

Roughly 15 years ago in a small Arizona town, Reddit user Iced_TeaFTW started a medical billing service to help patients understand why they owe (or actually don't owe) the money they're being billed for. After getting to know the surrounding community rather well, Iced_TeaFTW decided to open a side patient advocacy business called Angel Healthcare Advocates to help negotiate settlements for balances owed by patients. Though the patient advocacy business has amassed only about $500 so far, Iced_TeaFTW intends to build it into something bigger.

Just last year, Reddit commenter Louise Verity, who goes by mammalouise on the site, turned a small Etsy store for handmade products into a full-fledged home decor business. She now sells greeting cards, stationery, jewelry, art prints, and themed gifts for book lovers through her online store, Bookishly. With a booming wholesale business and three staff members, Verity says, Bookishly is now her only source of income.

If nothing else, this thread perfectly describes the benefits of accidents happening.